Mast cells are immune cells that are derived from hematopoietic progenitors from the bone marrow and mature in peripheral tissues. Mast cells are major effector cells of many allergic and inflammatory reactions and express high-affinity receptors for immunoglobulin E (IgE). Crosslinking of IgE receptors with IgE and specific antigen initiates mast cell activation, leading to the release of a wide spectrum of mediators such as histamine, lipid mediators, and many cytokines and chemokines. In rodents, two types of mast cells have been identified based on their phenotypic characteristics: connective tissue-type and mucosal-type. These two populations of mast cells differ in location, cell size, staining properties, ultrastructure, mediator content, and T-cell dependency. Human mast cells are distinguished on the basis of their protease composition. Human MCTC mast cells contain both tryptase and chymase in their granules and exhibit functional characteristics similar to those of connective tissue-type mast cells. MCTC mast cells are found predominantly in the skin and intestinal submucosa. Human MCT mast cells, on the other hand, contain only tryptase and exhibit functional characteristics similar to those of mucosal-type mast cells. MCT mast cells are predominant in the alveolar wall and gastric mucosa.
A protocol for generating mature human mucosal-type like mast cells (MCT) from CD34+ progenitors isolated from peripheral blood of human adult donors was published in 2006 (Wang et al. 2006. Journal of Immunological Methods, 309:69-74.). In 2007, Lappalainen et al. reported a method for generating mature human connective tissue-type like mast cells (MCTC) from human peripheral blood (Lappalainen et al. 2007. Clinical and Experimental Allergy, 37:1404-1414). Specifically, in the method described by Lappalainen et al., a time period of nine weeks is required to generate fully mature and functional human connective tissue-type like mast cells.